Association between ADHD medication and depression: a 10-year follow-up self-controlled case study.
Yunhye Oh 1, Yoo-Sook Joung 2*, Jinseob Kim 3
1Department of Child and Adolescent Psychiatry, National Center for Mental Health, Seoul, Korea., 2Department of Psychiatry, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea., 3Department of Epidemiology, School of Public Health, Seoul National University, South Korea.
Received: January 20, 2021; Revised: February 17, 2021; Accepted: February 17, 2021; Published online: February 17, 2021.
© The Korean College of Neuropsychopharmacology. All rights reserved.

Objectives: This study aimed to investigate the association between MPH use and the risk of depression.
Design: A population-based electronic medical records database from South Korea was used. We obtained claims data between January 2007 and December 2016 for 43,259 individuals aged 6 to 19 who were diagnosed with ADHD between July 1, 2007 and December 31, 2007. The final analysis was based on 2330 eligible participants. A self-controlled case series design was used to identify risk factors for major depressive disorder (MDD).
Results: An elevated MDD risk was found during the 90 days before MPH exposure, with an incidence rate ratio (IRR) of 12.12 (95% CI: 10.06 – 14.61, p < 0.0001). During methylphenidate treatment, the IRR was 18.06 with a 95% confidence interval of 16.67 to 19.56 (p < 0.0001), but it returned to baseline levels after day 31 of MPH treatment discontinuation. The IRR for patients aged 6 to 9 years was 13.11 (95% CI 9.58 to 17.95) during the 90 days before MPH exposure, and 17.7 (95% CI 15.6 to 20.08) during MPH treatment, but returned to baseline levels after discontinuation of MPH treatment.
Conclusion: We confirmed the temporal relationship between depression and methylphenidate use in young people with ADHD. Though the absolute risk is low, the risk of depression should be carefully considered, particularly in the period directly following the start of methylphenidate treatment
Keywords: ADHD medication, Methylphenidate, Depression, Self-controlled case study